In order to maximize training capabilities, a flight simulator may provide a marksmanship scoring device that is associated with a visual system.
A visual system includes an image generation subsystem, e.g. a computer image generator (CIG), combined with an image display subsystem. In one display subsystem, a raster scanned television display is employed to generate an out of the window view. The external environment seen by the trainee pilot as he looks out the window is produced as the beam of the television cathode ray tube (CRT) traces the raster across the CRT's viewing surface.
The CRT is normally presented to the pilot through an optical system that provides a collimated view. The optical system normally will distort the image to a small degree, and the distortion will vary with head position.
The normal helmet-mounted sight is used in conjunction with the pilot's head angle to aim weapons at a target. The helmet-mounted sight has a predictable aiming tolerance, and the pilot must keep his sight on the target within the normal system tolerance. The addition of the optical system (and other system errors that do not admit to being calibrated) adds additional error to the aiming record of the pilot. Modern simulators must eliminate these additional errors if correct pilot training and scoring is to be accomplished.
The scoring device associated with the visual system operates on the principle that if a simulated firearm is properly aimed at a target, an indication of a hit is recorded. To this end, an image of a target may be provided by the CIG and traced onto the CRT by a target projection unit. A gun-sighting unit, using a helmet mounted sensor (HMS), is aimed at the target. The gun sighting unit may be electrically synchronized with the target projection unit. An error measuring device, which is electrically responsive to the movement of the sighting unit, produces a voltage representative of any error between the trainee's aiming point and the projected image of the target. In this way, the marksmanship of the trainee is scored by recording the number of hits.
To obtain a desired realism, the visual system-scoring device combination should anticipate and compensate for equipment errors that tend to critically detract from the realism of the simulator. Equipment errors include, for example, scanline non-linearities or collimation errors. These equipment errors are manifest as distortions in the scanline, evidenced by comparing the ideal scanlines shown in FIG. 1A with the distorted scanlines shown in FIG. 1B or 1C.
It is observed from these figures that if the trainee relied on the above stated principle underlying the prior art scoring devices, namely that if the simulated firearm were properly aimed at a target, an indication of a hit would be recorded, the equipment errors would cause an accurate shot to be falsely scored as a miss.
Relevant prior art devices, as typified by U.S. Pat. No 3,849,910 entitled "Training Apparatus For Firearms Use" which issued Nov. 26, 1974 to R. B. Greenley, have not addressed the problem of equipment errors as related to marksmanship scoring devices. These devices therefore lack realism relative to an actual shooting situation.
The present invention provides an apparatus for correction of equipment errors that addresses the cited problems and improves upon the prior art by compensating for equipment errors while preserving all of the attributes of the prior art approaches. The present invention thus provides a visual system-scoring device combination which mitigates the disadvantages of the prior art devices and enhances the effective realism of the simulator.